Experimental and numerical analyses of double diffusive natural convection heated and cooled from opposing vertical walls with an initial condition of a vertically linear concentration gradient

Abstract

When a solution having a vertically linear concentration gradient is heated from a vertical wall and cooled from an opposing vertical wall, multi-layered roll cells separated by almost-horizontal sharp interfaces are observed. A Galerkin finite element method was employed for the numerical analyses of this double diffusive convection. Computations were carried out for the Prandtl number Pr = 6, the Lewis number Le = 100, an aspect ratio A = 4, the Rayleigh number Ra = 10 6 and a buoyancy ratio N = 10 or 20. Multi-layered roll cells with sharp and almost-horizontal interfaces were formed in the numerical simulation and then the concentration in each layer became almost uniform. The experiment confirmed the numerical results.